Skip over navigation
Red or Black
Age 11 to 14
ShortChallenge Level 
Each edge of the cube borders two faces.
As there are six faces, a minimum of three black edges will be required.
The diagram on the right shows that three black edges is enough.
This problem is taken from the UKMT Mathematical Challenges.
You can find more short problems, arranged by curriculum topic, in our short problems collection.
You may also like
Hallway Borders
What are the possible dimensions of a rectangular hallway if the number of tiles around the perimeter is exactly half the total number of tiles?
